1. Field of the Invention
This invention relates to keyboard entry systems, and more particularly, to such keyboard entry systems which are equipped with both contactless capacitance switches and contact switches.
2. Description of the Prior Art
Switches which may be used in keyboard entry systems for the entry of alpha-numeric or other information, include contact type switches and contactless type switches, such as capacitance switches, magneticallly sensitive switches using Hall elements, and the like. It is more desirable to use contactless switches, which excel in durability and reliability, in keyboard entry systems or the like, used, for example, as a terminal device for a computer. In keyboard entry systems having contactless switches, nevertheless, it is necessary, as the case may be, to also provide select switches, such as rotary switches, slide switches, and the like, which are constructed to select one of a plurality of switching contacts. However, since it is difficult to construct such select switches using contactless switches, keyboard entry systems requiring such select switches having contacts. Thus, in such keyboard entry systems, a circuit is required to separately scan the respective operating conditions of the two types of switches. Accordingly, construction and control operation of such systems are complex.